The present invention relates to agricultural harvesters and, more particularly, to axial flow combine harvesters having a threshing and separating unit with at least one generally longitudinally arranged rotor for advancing crop material along a generally helical path.
In conventional combine harvesters crop material is fed between a threshing cylinder and an associated threshing concave, which extend transversely to the direction of combine travel. Hereby the crop is threshed over a comparatively short distance. Axial flow machines use one or more longitudinally arranged rotors and associated concaves. Herein, crop material is subjected to a much longer threshing and separating action than in a conventional machine and therefore, the efficiency of axial flow machines is greater because a higher degree of separation is reached and the grain losses are reduced.
The owner wants to maximise the use of his combine harvester. Hence he desires to adapt it to a wide range of crops and crop conditions, such that the harvester can operate during an extended harvesting season.
On known axial flow combines the possibilities for changes are limited. Rotor speed and concave clearance may be adapted quite easily, but the concaves themselves are not that easily removed and replaced.
Accordingly there is a need for a versatile threshing and separating arrangement which makes it possible to adapt the combine harvester to a wide range of crops and crop conditions in a swift and effective manner.
According to one aspect of the present invention there is provided a combine harvester comprising:
a main frame;
a threshing and separating arrangement mounted to said main frame and including:
a generally cylindrical chamber having a generally longitudinal axis and comprising a separating concave assembly; and
a rotor assembly mounted for rotation in said chamber and comprising a generally cylindrical rotor body with a separating section associated with said separating concave assembly;
characterised in that:
said separating concave assembly comprises at least two separating concaves, the one located behind the other and taken from a choice of less and more aggressive separating concaves;
said chamber comprises mounting means operable to receive and hold each of said choice of separating concaves.
This structure enables the mounting of various types of concaves at the front and rear ends of the separating section, in order to adapt the combine to a wide range of harvesting conditions and crops.
Preferably the front and rear sections have identical mounting means, such that the same concave can be installed at wish in a front or rear position in the concave assembly. Hence there is no need for dedicated front or rear concaves, and before the end of their lifetime, the more worn front concaves can be exchanged with the less worn rear concaves.
The concaves may be of the more aggressive type comprising a grate constituted by spaced, longitudinally arranged slats and a set of curved wires extending transversely through the slats. They may also be of the more gentle type comprising a grate constituted by a curved plate having substantially rectangular apertures therein.
When the threshing and separating arrangement comprises left and right chambers, the separating concaves and their mounting means preferably are symmetrical with respect to their transverse middle plane, such that the concaves can be mounted invariably to the left or right chambers. This allows for reversal of the concaves after or during the harvesting season, such that the front, most worn part of the concave is turned to the rear of the chamber.
A similar structure can be applied to the threshing concaves at the front end of the chambers.
According to another aspect of the present invention there is provided a combine harvester comprising:
a main frame including side walls;
a threshing and separating arrangement mounted to said main frame and including a generally cylindrical chamber having a generally longitudinal axis and comprising a concave assembly comprising at least one removable concave; and
a cleaning assembly arranged below said concave assembly;
characterised in that
at least one side wall has an aperture therein for passing therethrough said removable concave, and a panel for closing said aperture; and
said combine harvester further comprises transverse rest means arranged between said side walls and between said threshing and separating arrangement and said cleaning assembly for resting thereon said removable concave during installation or removal of said concave.
Preferably the rest means are provided with an opening permitting the passage of threshed and/or separated grain to the cleaning assembly.
In one embodiment the rest means comprise a pair of transverse supports, extending between the side walls. In a preferred embodiment the supports are constituted by tubular members connected at their ends to side mounting members. The front support may extend at a lower level than the rear support, in order to adapt to the longitudinal inclination of the threshing and/or separating concave.